Forming blade holding core segments



Nov. 3, 1942. A. F. PFEIFFER 2,301,140

FORMING BLADE HOLDING CORE SEGMENTS 8 Sheets-Sheet l Filed NOV. 24, 1941Nov. 3, 1942. A. F. PFEIFFER 2,301,140

FORMING BLADE HOLDING CORE SEGMENTS Filed Nov. 24, 1941' 8 Sheets-Sheet2 1942- A. F. PFEIFFER FORMING BLADE HOLDING CORE SEGMENTS 8Sheets-Sheet 3 Filed Nov. 24, 1941 Nov. 3, 1942. 1 E 2,301,140

I FORMING BLADE HOLDING CORE SEGMENTS Filed Nov. 24, 1941 v I 8SheetsSheet 4 /z 0 m -i11 /2z, 7

Nov. 3, 1942. A. F. PFEIFFER I FORMING BLADE HOLDING CORE SEGMENTS 8Sheets-Sheet 5 Filed Nov. 24, 1941 /20 m ra v I! NOV. 3, 1942. PFElFFER2,301,140

FORMING BLADE HOLDING -CORE SEGMENTS Filed Nov. 24, 1941 8 Sheets-Shet 6a D m E: 1: I: 5::

' L L I Q 4 v s NOV. 3, 1942. A, pFElFFER 2,301,140

FORMING BLADE HOLDING CORE SEGMENTS Filed Nov. 24, 1941-v a Sheets-Sheet7 Patented Nov. 3, 1942 FORIVHN G BLADE HOLDING CORE SEGMENTS Albert F.Pfeifler, West Allis, Wis., assignor to Allis-Chalmers ManufacturingCompany, Milwaukee, Wis., a corporation of Delaware Application November24, 1941, Serial No. 420,263

26 Claims.

This invention relates generally to elastic fluid turbine wheels,diaphragms and the like formed by embodying the buckets or fluid passagedefining elements in a suitable core and by casting inner and outerdiaphragm ring segment forming members integrally about the free endportions of the buckets or fluid passage defining elements which projectfrom said core and more particularly to an improved core constructiontherefor.

In the construction of elastic fluid turbine diaphragm ring segments,for example, there are two known and accepted constructions which haveheretofore been employed for correctly positioning and maintaining thepartition or passage defining elements in their proper assembledrelation within the core box during the ramming operation, namely: (1)indestructible metal filler blocks which are disposed between the freeinner and outer end portions of adjacent blades and which may be removedeither before or after the core is baked, and (2) destructible fiberside walls which are removable from the core only after the baking ofthe core is completed and which have formed therein exactly fittedalined openings through which the end portions of the partition or fluiddefining elements extend.

The construction designated (1) above is time consuming and extremelycostly since each filler block has to be accurately made and hand fittedto exact dimensions, since the filler blocks and partition elements haveto be carefully assembled and the assembly accurately checked, and sinceall of these operations must be performed by persons having a highdegree of skill. Moreover, as soon as a filler block becomes slightlyworn, warped or otherwise deformed, it must be replaced and sincedeformation of the accurately fitted filler blocks frequently occurs,the cost of this type of construction is further increased. Furthermore,any error arising from the use of deformed or improperly fitted blocksor from the inclusion of foreign particles between the abutting surfaceson adjacent blocks and/or between the abutting surfaces on the blocksand the partition elements held therebetween is cumulative, therebyfrequently requiring a completed or nearly completed assembly to betaken apart, the dimculty corrected, and the parts reassembled.

The construction designated (2) above is also time consuming andextremely costly. For ex-- ample, each fiber side wall must beaccurately shaped to the requisite curvature and punch guides (one foreach of the openings through which a partition element extends) must behand filed therein and carefully checked before the partition elementretaining openings can be punched therein. Moreover, the fiber sidewalls (two are required for each core) must be leftin place to supportthe partition elements when the core is being baked and the applicationof heat during the baking operation renders the fiber side Wallssufficiently brittle to prevent their removal Without destruction,thereby necessitating making a complete new set of fiber side walls foreach core. Furthermore, after the fiber side walls have been removedfrom the core, fillet recesses must be cut by hand around both ends ofeach partition element Therefore, the primary object of this inventionis to provide an improved construction for core segments embodyingangularly spaced fluid pas.- sage defining elements which permit thecore segments to be constructed with a minimum of skilled labor, whichmaterially decreases thetime required to form a core segment, and whichinsures a high degree of accuracy heretofore unexcelled by highlyskilled labor. I

Another object of this invention is to provide an improved core boxstructure embodying means permitting unskilled labor to rapidly andaccurately position and secure in a core box an assembly comprising thefluid passage defining elements of a turbine diaphragm or wheel segmentand the filler blocks adapted to be disposed in abutting relationbetween the end portions of adjacent elements.

Still another object of this invention is to provide an improved corebox structure embodying means, which permits unskilled labor to rapidlyand accurately position and secure in a core box; an assembly comprisingthe fluid passage defining elements of a turbine diaphragm or wheelsegment and the filler blocks adapted to be disposed in abuttingrelation between the end portions of adjacent elements, which permitsthe box in-v eluding saidassembly to be readily rammed with core sand,and which permits the positioning and securing means to be readilyremoved from the box when the ramming operation is nearing completionwithout disturbing said assembly.

Still another object of this invention-is to provide an improved ringsegment core embodying the fluid passage defining elements of a turbinediaphragm or wheel in that the core is provided with means operative toprevent a radial deformation of the core during the baking operation andto permit the baked core to be readilypicked up and bodily moved withoutdanger of breaking same,

, The invention accordingly consists of the various methods, features ofconstruction, combina-.

tions of elements and arrangements of parts as fully set forth in theappended claims and in the,

Fig. 2 is a section taken on line II-Ili of Fig. 1;-

Fig. 3 is a top plan view of a core box embodying the invention withparts removed or broken away to better show the construction;

Fig. 4 is a transverse section taken on line IVIV of Fig. 3;

Fig. 5 is a transverse section taken on line V--V of Fig. 3 with thelower jig holding ring segment and its transversely extending supportingstrap removed;

Fig. 6 is a transverse section taken on line VIVI of Fig. 3; V

Fig. 7 is a transverse section taken on line VIIVII. of Fig. 3;

Fig. 8 is'a developed side view of the means for positioning andmaintaining the blades in the core box;

Fig. 9 is a partial section taken on line IX-IX of Fig. 3 with thefiller block clamping segments, the drag ring segments, and the fillerblocks removed;

Fig. 10 is a developed side view illustrating the outer series of fillerblocks in assembled relation with respect to each other and with respectto the end portions of the blades;

Fig. 11 is an end view of the right-hand end block shown in Fig. 10;

Fig. 12 is an end view of the left-hand end block shown in Fig. 10;

Fig. 13 is a top view of a fragment of the channel portion of the corebox with blades and filler blocks therein shown in section;

Fig. 14 is a view similar to that shown in Fig. 13 with the blades andfiller blocks shown in plan;

Fig. 15 is a section taken on line XVXV of Fig. 3 with the filler blockclamping segments, the upper jig ring, and the blades and filler blocksremoved;

Fig. 16 is a partial section taken on line XV'I-XVI of Fig. 15;

Fig. 17 is an exploded view of the end block structure of Fig. 16 tobetter show the arrangement of the coacting projections and recesses;

Fig. 18 is a partial section taken on line XVIII-XVIII of Fig. 15;

Fig. 19 is a bottom view of the top portion of the end block structuretaken on line XIXXIX of Fig. 18;

Fig. 20 is a section taken on line XXXX of Fig. 3; d

Fig. 21 is a section taken on line XXIXXI of Fig. 3;

Fig. 22' is a complete section taken on line XV-XV of Fig. 3;

Fig. 23 is a development of a section of the inner portion of the corebox taken on line XXIIIXX[II of Fig. 22;

Fig. 24 is a section similar to Fig. 21 showing the box partially rammedwith the upper jig holding ring removed and the core arbor and thesubstitute filler block clamping segments in place;

Fig. 25 shows the structure of Fig. 24 inverted on a mold board;

Fig. 26 shows the inverted structure of Fig. 25 with the base ringsegment and the lower jig holding segment removed;

Fig. 27 shows the structure of Fig. 26 with the with the blade holdingand spacing jigs removed and with the second core arbor and the copesegments in place;

Fig. 28 is an end view of the left-hand end of the inverted core boxwith the end plates removed;

Fig. 29 is an end view of the left-hand end of thefinished core;

Fig. 30 is a side view of the inner side surface of the finished core;

Fig. 31 is a side view of the outer side surface of the finished core;

Fig. 32 is a partial plan view of the unbaked core;

Fig. 33 is an end view of the core shown in Fig. 32;

Fig. 34 is a plan View of the drag portion of the pattern used informing a mold adapted to receive the core;

Fig. 35 illustrates a section of the drag portion of the pattern takenalong the line XXXV-XXXV of Fig. 34 as it appears in a mold flask rammedwith sand;

Fig. 36 is a sectional View showing the completed pattern supported inthe drag flask;

Fig. 37 is a sectional view showing the completed mold with the coredisposed therein;

Fig. 38 is a partial top view of the core box showing the manner inwhich the upper jig holding ring segment is secured in the core box;

Fig. 39 is a sectional view taken on line XXXIXXXXIX of Fig. 38;

Fig. 40 is an end view of the left-hand end of the core box showing theend plates in place; and

Fig. 41 is an enlarged view of the bottom portion of an intermediatefiller block.

Referring to the drawings. Fig. 1 shows a turbine diaphragm segment Iwhich was cast with the aid of a core structure embodying featuresconstituting the invention. The diaphragm segment I, of which atransverse section is shown in Fig. 2, comprises a series of spacedcurved passage defining elements 2 (hereinafter referred to as blades),an inner ring segment 3 and an outer ring segment i. The diaphragmsegment I is constructed by forming a core 6 (see Figs. 29, 30, 31 and3'?) in which the blades 2 are accurately held in predetermined spacedangular relation with the inner and outer end portions of the bladesextending freely beyond the inner and outer side surfaces of the coreand by casting integrally thereto, i. e., to the free end portions ofthe blades, the inner and outer ring segments designated 3 and 4,respectively. A complete diaphragm is usually made by casting twooversize segments which are then machined to provide two 180 segmentshaving the requisite dimensions. However, neither the number of segmentsemployed in forming a complete diaphragm nor the nature of the bladesemployed in forming the segments are essential features of thisinvention and a further description in this connection is believedunnecessary for a complete understanding of the core box structure 1used in forming the core 6.

Referring particularly to Fig. 3, it is seen that the core box structure1 comprises a base ring segment 8, a lower jig holding ring segment 9disposed on said base ring segment in spaced concentric relation withrespect to the side edges thereof, a pair of inner and outer bladepositioning and holding jig segments H and I2, respectively, which aredisposed on the jig holding ring segment 9 in spaced concentric relationwith respect to the side edges of the said base segment and with respectto each other, a pair of inner and outer drag ring segments I3 and M,respectively, which are disposed on said base ring segment in spacedconcentric relation with respect to said pair of jig segments and withrespect to each other, the blades 2 which are positioned and held inpredetermined spaced angular relation by the inner and outer jigsegments H and I2, respectively, with a portion of the opposite end ofeach blade abutting the opposed channel forming side surfaces presentedby the pair of inner and outer drag ring segments l3 and 4,respectively, the inner and outer series of filler blocks It and I1,respectively, which are disposed in spaced concentric relation betweenthe inner and outer end portions of adjacent blades, the upper jigholdin ring segment I 8 which is disposed in spaced con centric relationbetween the opposed channel forming side surfaces presented by the innerand outer drag ring segments l3 and I4, and the inher and outer fillerblock clamping ring segments l9 and 2|, respectively, which are securedto the top portions of the inner and outer drag ring segments l3 and Min spaced concentric relation with respect to the upper jig holding ringsegment H! and with respect to each other.

Referring also to Figures 4 and 5, it is seen that the base ring segment8 may comprise a flat ring segment bottom member 22 having its endsrigidly connected by a cross member 23, and a pair of inner and outerbase members 24 and 26 having similarly shaped top surfaces 21 and 28,respectively. Base members 24 and 2B are positioned on and secured tothe bottom member 22 by any suitable means (not shown) and in spacedconcentric relation with respect to the side edges thereof and withrespect to each other so as to form therebetween a channel 29 adapted tosnugly receive therein the lower jig holding ring segment 9. The jigholding segment 9 is properly positioned in the channel 29 with its topsurface substantially flush with the surfaces of the uppermost steps onthe base members 24 and 29. Referring also to Figs. 3, 5, 6 and 7, it isseen that the positioning means comprises a plurality of transverselyextending straps 3| each of which is secured to the underside of the jigholding segment 9 by a cap screw 32 and each of which is disposed withina pair of radially extending alined rooves 33 and 34 provided in thestepped top surfaces of the base members 24 and 26, respectively, aplurality of pins 35 (see'Fig. 7) which extend downward from theunderside of the jig holding segment 9 and into the sockets 36 providedin the bottom member 22, and a pair of removable rods 31 which extendthrough alined openings in the base members 24 and 26 and the jigholding segment 9 as is shown in Fig. 3. The bottom member 22 isprovided, as shown in Fig. 6, with openings 38 into which the strap 3|and the head of the cap screw 32 project. The top surface of the innerand outer radially extending portions of the strap 3| which lie in thealined grooves 33 and 34 are stepped to form continuations of thestepped top surfaces 21 and 29 presented by the base members 24 and 2G,respectively, as is best shown in Figs. 3 and 6.

The lower jig holding ring segment 9 is provided in its top surface witha pair of inner and outer channels 39 and 4|, respectively, which arepreferably of rectangular shape when viewed in transverse cross sectionand which are disposed adjacent the inner and outer edges of the jigholding segment 9 and in spaced concentric relation with respect to eachother and with respect to the concentric surfaces provided by thestepped top surfaces of base segments 24 and 29,.respectively. The lowerportions of the blade positioning and holding jigs H and I2 fit snuglywithin the inner and outer channels 39 and 4|, respec tively, as isclearly shown in Figs. 6 and '7 and are removably secured therein bymeans of a plurality of pairs of screws 42 which extend through pairs ofbores 43 provided in the jig holding segment 9 and into the alined andinternally threaded bores 44 and 46 provided in the bottom side of theinner and outer jig segments II and H, respectively, as is shown inFigs. 9 and 20. The portions of the inner and outer jig segments H andI2 which extend above the top surface of the J'ig holding segment 9 areprovided with pairs of alined transverse notches 41 and 48 whichterminate in identical undercut portions 49 and 5|, respectively,adapted to receive therein longitudinally spaced intermediate portionsof the outlet edge of a curved blade as is best shown in Figs. 8, 9, 13and 14.

In this connection, it should be particularly noted (see Fig. 8) thatthe undercut portions 49 and 5| are each defined by downwardly inclinedopposed surfaces 52 and 59 and by an end surface 54; that the opposedportions of the surfaces 52 and 53 are substantially parallel and spacedapart a distance only slightly greater than the thickness of thatportion of the outlet edge of the blade which is inserted therein; thatthe undercut portions of the pairs of notches are in radialialinement(see Figs. 3, l3 and 14); and that when the outlet edge portion of acurved blade is insertedtherein, the weight of the blade acts to hold(1) spaced intermediate portions of the outlet edge in engagement withthe end surfaces 54, (2) spaced portions of the concave surface whichare immediately adjacent said outlet edge portions, in engagement withthe upper surface 52, and (3) spaced portions of the convex surface,which are remote from the said outlet edge portions, in engagement withthe lower surface 53 as is clearly shown in Fig. 8. In addition, itshould also be particularly noted (see Fig. 9) that the blades 2 have anintermediate outlet edge portion of reduced thickness, and thattherefore only relatively small portions of the outlet edge of eachblade on either side of the jig holding segment 9 are shown as actuallyengaging the top steps of the surfaces 21 and 29. However, when bladesare employed which have an outlet edge of substantially'uniforrnthickness, it should be apparent that the entire width of the said topsteps would be engaged by the overlying edge portions of each blade. Thearrangement is preferably such that the top surfaces of the top stepsare substantially flush with the top surface of the jig holding segment9 and that the'lowerrnost edges of the undercut portions 49 and 5|, i.e., the edges formed by the junction of the lower surface '53 and theend surface 54, are also substantially flush with the top surface of thejig holding segment 9 and with the top surfaces of the said top steps.Consequently, when the thickness of the outlet edge of each blade isequal to the width of the end surface 54, portions of the outlet edge ofeach blade will engage the top surfaces of the said top steps in themanner just described. Obviously, if the thickness of the outlet edge ofthe blade is made greater than the width of the end surface 54, theoutlet edge of the blade cannot be inserted into the undercut portionsof the notches without deforming the notch or blade or both, and thepreferred procedure in order to allow for reasonable manufacturingtolerances is to make the outlet edge of the blade just equal to orslightly less than the width of said end surface. Therefore, in actualpractice, the outlet edge of the blade may be spaced above the topsurfaces of the said top steps a distance equal to the maximumpermissible tolerance.

Referring particularly to Fig. 7, it is seen that the inner and outerdrag ring segments I3 and I4 are provided with stepped top and. bottomsurfaces 56, 51 and 53, 59,, respectively, and that the bottom surfacesof the segments I3 and I 4 are provided with internally threaded bores6| and 62, respectively, arranged for alinement with the bores 83 and 64in the base members 24 and 25 which bores are in turn alined with thebores 65 and 6! provided in the .bott om.member 22. Bolts 68 and 59removably secure the drag ring segments I3 and I 4 in spaced concentricrelation on inner and outer concentric portions of the stepped topsurfaces 2'! and 28 which are presented by the base members 24 and26,respectively. The radial width of the drag ring segments is less thanthat of the base members 24 and 26 and the opposed channel forming sidesurfaces of the segments I3 and I l coact andform with exposed portionsof the stepped top surfaces 27 and 28 spaced concentric surfaces adaptedto position and retain thereagainst the inner and outer series of fillerblocks I and I I, respectively, which are to be assembled in spacedconcentric relation between the inner andouter end portions of adjacentblades. The length of the blades 2 and the spacing of thedrag ringsegments I3 and I4 are such that when the outlet edges of the blades areinserted in the pairs of alined notches 41 and 48 which act tocorrectlyposition and hold the blades in a predetermined spaced angularrelation, a portion of each end of each blade abuts the adjacent channelformingside surface presented by said drag ring segments as is bestshown in Figs. 13 and 14. The lower step of the top surfaces 56 and 58of the drag rings I3 and I4, respectively, are provided with metalfacing ring segments 7 55 and 60, respectively, which are preferablyremovably secured thereon by any suitable means such as the countersunkscrews 65. V v j Referring to Figs. -14, inclusive, and 4|, it is seenthat the outer series of filler blocks II comprises the end blocks 1Band ,II and a plurality of identical intermediate blocks I2. Each of theblocks III, II and I2 has stepped top and bottom surfaces I3 and I4,respectively, which are similar, i. e., all steps onthe top surfaces areidentical and all steps on the bottom surfaces are identical, and theouter side surfaces of these blocks are preferably made to conform withthe curvature of the inner side surface of the outer drag ring segmentI4 as is best seen in Figs. 13 and 14. The end block I0 has a planeouter end surface 89 and an oppositely facing inner end surfacel'Ecomprising aplane radially extending top portion I5, a concave radiallyextending intermediate portion 11 which conforms with and is adaptedtoengage the convex surface of a blade 2, and a bottom portion includinga radially extending edge m and a plane radially extending surface I9.The edgeI8 is formed by the intersection of the concave surface ,portionI7 and that portion of the stepped bottom surface I4 which is adapted toengage thetop step of the surface 23 on the bottom member 26. The topportion of the block II! is of greater radial thickness than the bottomportion thereof and its inner side surface BI is preferably formed byupper and lower plane surfaces being connected by, a portion of compoundcurvature as shown in Fig. 11. The lower portion cf the concave surface11 is extended inwardly a slight distance beyond the lower portion ofthe inner side surface BI so as to form therewith a fillet formingprojection 82.

Each of the intermediate blocks f2 has an inner end surface 83 which isidentical to the surface I5 on the end block 18 and an outer end surface84 comprising a plane radially extending top portion 86 which iscomplementary to the similar surface It on the end block IS, a convexradially extending intermediate portion 8! which conforms with and isadapted to engage the concave surface of a blade 2, and a bottom portionincluding the plane radially extending surfaces 88, 89 and 90 as bestseen in Fig. 41. The top portions of each block I2 are also of greaterradial thickness than the bottom portions thereof and its inner sidesurface 8|, which is formed in the same manner as the side surface tilon the block I0, is provided with a pair of inwardly extending filletforming projections 92 and 93 which merge into a single projection atthe toe of the block as is clearly shown in Fig. 10 and Fig. 41. Thefillet projection 92 conforms with the similar projection 82 on the endblock I51. The end block H has a plane outer end surface 9 and anoppositely facing inner end surface 86. The surfaces 94 and 98 areidentical to the outer end surfaces 88 and 84 on the end andintermediate blocks I0 and I2, respectively, and a repetition of thedetailed description of such surfaces is believed unnecessary for acomplete understanding of the invention. In addition, the top portion ofeach block II is of greater radial thickness than the bottom portionthereof and its inner side surface 9! is provided with an inwardlyextending fillet forming projection 98 corresponding to the filletforming projections 93 on the intermediate blocks I2. The side surfaceQI is also formed by plane and curved surfaces as set forth in thedescription of end block IS.

The inner series of filler blocks It comprises, as best shown in Figs.13, 14 and 23, the end blocks IGI and IE2 and a plurality ofintermediate blocks H13. Each of the blocks IfiI, M32 and IE3 hasidentically stepped top surfaces hi l and identically stepped bottomsurfaces I which are adapted to engage the exposed portion of thestepped surface 21 on the base member 24. The blocks Ifll, I82 and IE3have inner side surfaces which are made to conform with the outer sidesurface of the inner drag ring segment I3 and have outer side surfacesI96, I07 and H0 which are similar to the inner side surfaces SI, 92 and91,, respectively, on the outer blocks IE, II and I2. The end block IIlIhas a plane end surface I58 and an oppositely facing inner end surfaceI39 which end surfaces are similar to the outer and inner end surfaces89 and i5, respectively, on

the end block I0. The end block I62 has oppositely facing inner andouter end surfaces III and H2 of which the surface IE2 is similar to thecorresponding end surface S t on the outer end block II. However, theend surface III, which is somewhat similar to the end surface 98 on theend block II, differs therefrom in that the plane and convex portionsthereof are made to extend parallel to the plane and concave portions ofthe surface 83 on the intermediate block I2 as is best shown in Fig. 13.The intermediate blocks I03 have oppositely facing end surfaces H3 andH4 with respect to which the surface H3 is identical to the surface I @9on the end block IUI and the surface H4 is identical to the surface I II on the end block I IE2. In other words, the surface III on the endblock I62 is made to extend parallel to the surface I I3 on the adjacentintermediate block I03. This construction which permits the inner fillerblocks to be withdrawn from between the blades by an inward radialmovement thereof is clearly shown in Figs. 13, 14 and 23.

Referring to Figs. 3, 15, 16, 17, 18, 22 and 23, it is seen that the endfiller blocks and IM of alined notches 41, 48 and the arrangement of areheld from being pushed out the end of the core box by means of inner andouter end blocks H6 and H1 having plane inner end surfaces H8 and H9,respectively. The arrangement is such that the plane end surface I I8 ofblock H6 is disposed in abutting relation against the plane end surfaceof the inner clampingring I9, the inner drag ring segment I3 and againsta portion of the plane end surface I08 of the end filler block IOI, andthat the plane end surface H9 of block H1 is disposed in abuttingrelation against the plane end surface of the outer clamping ring 2|,the outer drag ring segment I4 and against a portion of the plane endsurface 80 of the end filler block 18. Each of the blocks H6 and I I1comprises separable top and bottom portions I20, I2I and I22, I25,respectively. The top portion I is provided on its underside with aprojection I23 adapted to fit within the recess I24 provided in the topsurface of thebottom portion [2i and the top portion I22 is provided onits undersidewith a-projection I26 adapted to fit within the recess I21provided in the top surface of the bottom portion I25. The underside ofthe bottom portions I2I and I25. are provided with projections I28 andI29 adapted to fit within recesses 1 HI and I32, respectively, whicharerformed by blocks I33 and I34 being secured on the lowermost step ofthe surfaces 21 and 28 in spaced opposed relation with respect to theadjacent end of the drag ring segments I3 and I4, respectively, as isbest shown in Figs. 15 and 16. Each end of the drag ring segments I3 andI4 is provided with extensions I36 and I31, respectively, which presentplane opposed side. surfaces I38 and I39 adapted to engage the planeside surfaces MI and I42 on the end blocks H6 and H1, respectively, andprevent a transverse movement of said end blocks relative to the dragring segments and the end filler blocks I3, 2' I4 and 10, I02,respectively. The extensions I36.

and I31 terminate flush with the plane outer end surfaces of .the blocksH6 and H1 and with the plane end surfaces presented by the base members24 and 26 as is best shown in Figs. 3, 15, 16, 18 and 22, and a pair ofcoactingend plates I43 and I44 (see Fig. 40) are adapted to be removably secured in abutting relation against said surfaces by means ofthe stud bolts I46.

Assuming that the core box has been com pleted to the extent indicatedin Figs. '1 and 15; i. e., that the lower jig holding segment 9 including the jigs I I and I2 has been inserted in the base ring segment 8,that the drag ring segments have been positioned onand secured to thebase ring segment 8, and that the end blocks llli and H1 are in place;the next step is to posithe jigs II and I2 and the end filler blocks 10and IN is such that when a blade 2 is positioned and held by the saidadjacent pair of notches, the end portions of the convex surface of theblade abut the entire concave portions of the inner end surfaces 15 andI09 on the end filler blocks 10 and IN, respectively, as is clearlyshown in Figs. 10 and 23. An outer intermediate filler block 12 is thenpositioned in the box with its outer side surface abutting the innerside surface of the drag ring segment 14 and with its stepped bottomsurface 14 engaging the exposed portion of the stepped surface 28 onbase member 26 and so that the outer end surface 84, which comprises theplane surface 80, the convex surface 81, and the plane surface 83, abutsthe plane surface 16 on the endfiller block 10, the outer concave endportion of the blade 2, and the outer end portion of the outlet edgesurface of the blade 2, respectively, as is clearly shown in Figs. 10,13 and 14. An inner intermediate filler block I03 is then positioned inthe core box with its bottom surface I05, its inner side surface, andits end surface H4, which includes plane and convex surfacescorresponding to the surface portions 86,

81, 88, 89 and 80 on the outer filler block 12,

abutting the exposed portion of the stepped surface 21, the outer sidesurface of the drag ring segment I3, the inner margin of the plane topportion of the surface I89 on the end block IIH, the inner end margin ofthe concave surface of the blade 2, and the inner end margin of theoutlet edge surface of the blade 2, respectively, as is clearly shown inFigs. 13, 14 and 23. In actual practice, an inner and an outer fillerblock are placed simultaneously within the core box in the positionsjust described and the blade and filler block assembly is continued byalternately inserting a blade and a pair of inner and outer intermediatefiller blocks. When the requisite number of blades has been inserted asjust described, the assembly is completed by inserting the inner andouter end filler blocks I02 and H which are held in place in the corebox by a retaining end block assembly which is identical to thatdescribed for the end filler blocks 10 and IOI. Consequently, a furtherdescription in this connection is believed unnecessary for a completeunderstanding of the invention.

When the filler block, the blades and the retaining end block assemblieshave been completed as just described, the blades 2 are securely lockedin their assembled relation by placing thereon, i. e., on their inletedges, the

' upper jig holding segment I8 which has secured tion the end fillerblocks 10 and IOI in the.

core box with their stepped bottom surfaces 14 and, I05 engaging theexposed portions of the stepped surfaces 28 and 21, respectively, on thebase members 26 and 24, with their outer and inner side surfacesabutting the inner and outer side surfaces, respectively, of the dragring seg ments I4 and I 3, and with their plane end surfaces 80 and I88abutting the exposed portions of the plane inner end surfaces H9 and H8on the end blocks I I1 and H6 as is best shown in Figs. 22 and 23. Thenext step is to insert the outlet edge of a blade 2 into the adjacentpair in its underside, a projecting jig segment I41 provided withnotches I48 arranged to engage the inlet edges of the blades 2 in themanner best shown in Figs. 8 and 9. preferably positioned on theunderside of the jig holding segment I8 by means of a channel I49 whichis formed midway between the side edges of the segment I8 and which isadapted to snugly receive therein, a portion of the jig segment I 41.The jig segment may be removably secured in the channel I43 by anysuitable means, such as one or more of the screws I50 shown in Figs. 8and 20. The upper jig holding segment I8 is positioned directly abovethe lower jig holding segment 9 and each end is rigidly connected to theunderlying end of the segment 9. The connecting means (see Fig. 8)comprises an internally threaded bore I5I which extends The jig I41 isthroughthe segment I8,1.a non-threaded bore ltllwhich extends through'the segment 9 in alinement withnthe bore and which terminates in anupper counterbored portion I53, a stud having an upper threaded portionI54 extending within the bore I5I, an enlarged intermediate .portion I56which fits within the counter-bore I53 and which abuts the underside ofthesegment ii andanexternally threaded reduced portion I51 which extendsthrough the bore I52 and is engaged by a nut I58. It should beparticularly noted that thejig I51 engages the-inlet edge, of each blade2 at ,a point which is midway between the; ends of the blade and whichisalso midway between the longitudinally spacedportions of the outlet edgeof the blade engaged by a pair of the .alined notches ll and.

spectively, on the inner and outer drag ring seg-.

mentswlth the stepped bottom surfaces. l 5% and Itl engaging thecomplementary stepped top surfaces Iil l and I3 presented by the innerand outer series of fillerv blocks it and ii, respectively, as shown inFig. .21. The top surfaces of the clampingring segments is and 26 aresubstantially flush with the plane surfaces presented by top steps ofthe surfaces 56 and 581 on the drag.

holding segment 28 so as to facilitate the ramming operation. .Beferringto Figs. 38 and bit is seen that the upper surfaces of the filler blcclrclamping segments I9 and H are provided with a pair of radially alinedgrooves I63 .and ltd-and.

the top surface of the upper jigholding segment I3 is provided withasimilargroove ltia arranged for alinement with the grooves i639 andM53.- A metal strap IE7 is inserted in said grooves and is removablysecured to the filler block clamping segments I9 and ii by any suitablemeans such as the screws I58 so as to prevent the intermediate portionof the jig holding segment I8 from springing upward relative to theinlet edges of the blades. The end piatesMB and I44 are now secured tothe ends of the box (see Fig.40) thus rendering the box ready for theinitial ramming operation. 1 7

Sand or other suitable core forming material, hereafter referred to assand, is now rammed by hand or blown into the space between the bladesuntil the box is filled with sand to a point slightly above the inletedges of the blades, i. e., the edges engaged by the-jig I li, whereuponthe end plates i 33 and Hi l are partially removed which permits theupper jig holding segment I3 and the jig to a depth sufficient tosupport the metallic ring segment arborIES out of contact with the inletedges of the blades as shown in Fig. 24. Usually a depth ofapproximately one-quarter of an inch is sufficient. The ends of thearbor ltd are removably connected together: by :a =tie= rod-4110. 2: Itshouldflalsobe' noted, particularzzreferenceis being had to Fig. 24,that the filler block clamp-.

ing segments, which were removed. either when i the upper'jig holdingsegment; I8- was-.,removed or after the arbor lfifirwasr placed in -the'box; have been replaced by a new set ,of clamping segr-z ments iii andH2 which differ from segments.

l9 and 2 I only inthat their opposed side surfaces:- "5 convergeupwardly with respectgto each other.:. The ramming of the core box isthen :continued until, the boxiis filledwith sandto' a. point sub-.

stantially flush with, the. topxs'surfacesr-of the: clamping segmentsIll "and I12." and the molds" board. H3115 placed overthecorebox andJthaentire structure is then inverted'to the position: 2.

shown in,Fig.'.;25.

The next stepin completing the; core is to are-- move thebase segment 8which :includes the 1: bottom member EZ and the inner and outer base:members Hand 26 from the drag-ring segments 1 l3 and I4 and from thelower jig holding seg-..

ment 9 and the strapsil which. are secured '1 This step is readilyaccomplished byv thereto. first. removing the bolts 68*and t9..(see.Fig;.7) and then lifting the entire basesegment. Next,

the lower-:jig hold segment. 9 is removed from i the jigs. II and I2which is readily accomplished. a by first removing the screws G2 andthenbodilyr lifting theujig holding segment 9 together with, the straps3i which, are secured thereto. I When this has been done, the screws 42are then. in-

serted in the jigs I I and I 2.1 The resulting strucel;

ture conforms withthat shown in Fig..26." Them: jigs II and I2 cannow bereadily removedffrom;v the outlet edges of the blades 2 and without af-.

fecting .a movementjthereof ,simply'by' grasping:

or tapping the screws 42 to effect a movement of 1 the jigscircumferentially and upward with're-v spect to the outlet edges of theblades .(the neces-.

sary direction of movement is apparent from a consideration of Fig; 8when inverted) a sufficient distance to. free the undercut portions ofthe. pairs of notches 4"! and 48 'from'the outlet edges of the blades.

The core box is then completed preparatory to the final rammingoperation, by placing on. the drag ring. segments, the inner and outercope segments I'l land I15, respectively, which have: the underside oftheir end portions provided with" recesses IT! and I78, respectively,adapted to,

receive therein the projections I29 and I28 on I the bottom .endblockportions I25 and I2I, re-I spectively. The bottom surfaces of the copeseg-.

ments I74 and I15 are'identical to the stepped,

surfaces. 21 and 28 presentedby. thebase mem-- bers 24 and 26,respectively, and the cope segments are positioned and removably' heldwith their bottom' surfaces engaging the'drag ring segments [3 and I4and the inner and outer series of filler blocks-I6 and I! by anysuitable meanssuch as the. dowel pins I83 shown in Fig. 27. The oppositeend portions of the cope segment I'M coact with the endsof the drag ringsegment. It, the bottom end block portions I25 (there being one suchblockportion at each end of the'box) the plane end surfaces on thefiller blocks It and H, and. with the inner surfaces of the end platesandforms therewith a space (see Fig.28) into which sand is rammed toform the laterally extending projection I19 adjacent the ends of-thecore Gas shown in Figs. 29, 30, 31 and 33. The opposite ends of the-copesegment I75 coact with theends of the drag ring segment I3,

the bottom-end block portions I2I (there being one such block portion ateach end of the box), the plane end surfaces on the filler blocks IOIand I52, and with the inner surfaces of the end plates and formstherewith a space (see Fig. 28) into which sand is rammed to form thelaterally extending projection ISI adjacent the ends of the core 6 asshown in Figs. 29, 30, 31 and 33.

The outlet edges of the blades are now covered with sand (the end platesI43 and I44 having been partially removed to permit the removal of thejig holding segment 9 and the jigs I I and I2) and ring segment arborI82, which is similar to the arbor I59, is placed thereon and the endsof the arbor are removably connected together by a tie rod I83 which isalso similar to tie rod I10. The core box structure shown in Figs. 2'7and 28, is now dismantled except for the inner and outer series offiller blocks I 6 and I1 and the filler block clamping segments HI andI12 which are preferably made of metal, such as aluminum, so as to alsofunction as drying segments, by removing, in the order named, the endplates I43 and I64, the cope segments I14 and I15, the

drag ring segments I3 and I4, and the portions of the end blocksdesignated I2I and I25. The core together with the remaining portions ofthe core box is shown in Figs. 32 and 33. The core is now ready forbaking and this is accomplished by placing the structure shown in Figs.32 and 33 in a suitable oven (not shown) wherein the core is heated toand maintained at the requisite temperature for a predetermined time.Prior to the insertion of the core structure within the baking oven, thefiller blocks, which are also made of metal such as aluminum tofacilitate drying, are preferably withdrawn from the core a slightdistance in the radial direction in order to prevent the expansion ofthe blocks from eX- erting a, force on the blades tending to move same.Withdrawal of the inner series of blocks in the radial direction ispermitted by forming the end surface II4 substantially parallel to thesurface H3 as is best shown in Figs. 13 and 23. In addition, theconnections between the ends of the arbors I39 and I82 and the ends ofthe tie rods I19 and I83 are loosened in order to permit the freeexpansion thereof during the baking operation to thereby prevent damageto the core. After the core has been baked and cooled, the inner andouter series of filler blocks I6 and I1 are entirely removed and theconnections between the ends of the arbors I69, I82 and the ends of thetie rods I19, I83 are again made secure in order to aid in preventingdeformation of the core while it is being removed from the mold boardand placed in the mold. The filler block clamping and drying segments HIand I12, which also function as a support for the filler blocks and thecore as shown in Fig. 33, remain on the mold board I13 when the core isremoved.

The dismantled core box structure including the previously used fillerblocks and a new set of blades can be readily reassembled and a new coresegment quickly formed in the manner just described. Obviously, noparticular skill is required in this connection, and as a result thecore segments can be rapidly formed with a minimum of expense, therebymaterially reducing the cost of making cast diaphragm segments. Inaddition, the accuracy of diaphragm segments cast with the aid of coresmade in accordance with this invention has in all cases been equal orsuperior to those made with cores constructed by highly skilledmechanics in accordance with the methods heretofore employed.

Referring to Figs. 34 and 35, it is seen that the drag portion I84 ofthe pattern, which is preferably used in forming a mold adapted toreceive the core 6 preparatory to casting the diaphragm segment I shownin Figs. 1 and 2, comprises the inner and outer segments I86 and I81 forproducing in the mold spaces corresponding to the portions of thediaphragm segment designated 3 and 4, respectively, a plurality of gateforming portions I88 which extend radially outward from the point atwhich the metal is to be introduced to the inner periphery of thesegment I83, a plurality of radially extending gate forming bridgingmembers I89 arranged to connect outer portions of the inner segment I86with the outer segment I81 across the core space forming portion I9I,and the match board I92. The first step in forming the mold is to placethe drag portion I84 on a mold board I93, then place a flask I94therearound and ram the same with sand to produce the structure shown inFig. 35. When this has been done, the flask is inverted on the moldboard, the match board I93 removed from the drag portion I84, and thecope portion I95 of the pattern is added to produce the structure shownin Fig. 36. The next step is to place the cope flask I96 on the flaskI94, ram the same with sand, lift the flask I96 from the flask I94,remove the pattern from the flask I94, place the core blocks I91 and I98in the space adapted to receive the core 6, place the core 6 in saidcore receiving space, insert the core blocks I99 and 20I, and place theflask I96 on the flask I94 which completes the mold as shown in Fig. 37.The metal is poured into the mold through the central sprue 202 andafter the casting operation has been completed and the casting cleaned,all that remains to be done is to machine finish the casting to thedesired dimensions. The pattern structure and the manner in which themold is formed are merely illustrative of a practical construction forusing a core formed in accordance with this invention, and it shouldtherefore be understood that it is not desired to limit the invention tothe exact methods and details of construction herein shown and describedas various modifications within the scope of the appended claims mayoccur to persons skilled in the art.

It is claimed and desired to secure by Letters Patent:

1. In a core box for use in forming turbine blade holding core segmentsembodying spaced curved blades extending transversely therethrough andpresenting inner and outer free end portions adapted to have inner andouter ring segments cast integrally thereto, a bottom and drag ringconstruction comprising a base ring segment, a pair of inner and outerdrag ring segments disposed on said base ring segment adjacent the edgesthereof and in spaced concentric relation with respect to each other,and a pair of inner and outer jigs disposed on said base ring segmentbetween and in spaced concentric relation With respect to said pair ofdrag ring segments and in spaced concentric relation with respect toeach other, said pair of jigs being shaped to engage longitudinallyspaced intermediate edge portions of blades inserted therein and tothereby position and firmly hold the blades in a predetermined angularrelation.

2. In a core box for use in forming turbine blade holding core segmentsembodying spaced curved blades extending transversely therethrough andpresenting inner and outer free end portions adapted to have inner andouter ring segments cast integrally thereto, a bottom and drag ringconstruction comprising a base ring segment, a pair of inner and outerdrag ring segments disposed on said base ring segment adjacent the edgesthereof and in spaced concentric relation with respect to each other,said drag ring segments coacting and forming with said base ring segmentspaced concentric surfaces shaped to position and retain thereagainstinner and outer series of filler blocks, and a pair of inner and outerjigs disposed on said base ring segment between and in spaced concentricrelation with respect to said inner and outer filler block positioningand retaining surfaces and in spaced concentric relation with respect toeach other, said pair of jigsbeing shaped to engage longitudinallyspaced intermediate, edge portions of blades inserted therein and tothereby position and firmly hold the blades in a pre-,

determined angular relation.

3. In a core box for use in forming turbine blade holding core segmentsembodying spaced curved blades extending transversely therethrough andpresenting inner and outer freeend portions adapted to have inner andouter ring segments cast integrally thereto, a bottom and drag ringconstruction comprising a base ring segment, a pair of inner and outerdrag ring segments disposed on said base ring segment adjacent the edgesthereof and in spaced concentric relation with respect to each other,said drag ring segments coacting and forming with said base ring segmentspaced concentric surfaces shaped to position and retain thereagainstinner and outer series of filler blocks, and a pair of inner outer jigsdisposed on said,

base ring segment between and in spaced concentric relation with respectto said inner and outer filler block positioning and retaining surfacesand in spaced concentric relation with respect to each other, said pairof jigs being shaped to engage longitudinally spaced intermediate edgeportions of blades inserted therein and to thereby position and firmlyhold the blades in a predetermined angular relation, and said pair ofdrag ring segments being spaced apart a distance commensurate with thelength of the blades to be positioned and held in said pair of jigs soas to form with the exposed top portion of said base ring segment andwith said jigs a channel in which the blades and filler blocks can bequickly and accurately assembled simply by alternately placing inabutting relation, on said concentric positioning and retaining surfacesand in said pair of jigs, a pair of inner and outer filler blocks and ablade, respectively.

4. In a core box for use in forming turbine blade holding core segmentsembodying spaced curved blades extending transversely therethrough andpresenting inner and outer free end portions adapted to have inner andouter and firmly, hold thehbla'des ina predetermined a mia;

In a core box for use in forming turbine blade holding core segmentsembodying spaced curved blades extending transversely therethrough andpresenting inner and outer free portions adapted to have inner and outerring segments cast integrally thereto, a bottom and drag ringconstruction comprising inner and outer base members disposed in spacedconcentric relati-on, a jig holding ring segment disposed between saidbase members, a pair of inner and outer jigs disposed in spacedconcentric relation on thetop portion of said jig holding ring segment,saidlpair of jigsbeing shaped to engage longitudinally spacedintermediate edge portions of blades inserted therein to therebyposition and firmly hold the blades in a predetermined angular relation,and a pair of inner. and outer drag. ring segments disposed in spacedconcentric relation and coacting with said base members to formtherewith spaced concentric surfaces shaped to position and retainthereagainst inner and outer series of filler blocks adapted to beassembled between the inner and outer end portions of blades held insaid pair of jigs.

6. In a core box for use in forming turbine ladeholding core segmentsembodying spaced curved blades extending transversely therethrough and.presenting inner and outer free end portions adapted to have inner andouter ring ment, said pair of jigs being shaped to engage longitudinallyspaced intermediate edge portions of blades inserted therein to therebyposition and firmly hold the blades in a predetermined angular relation,and a pair of inner and outer drag ring segments disposed in spacedconcentric relation and coacting with said base members to formtherewith spaced concentric surfaces shaped toposition and retainthereagainst inner. and outer series of filler blocks adapted to bevassembled between the, inner and outer endportions of blades held'insaidpair of jigs,

.said jigs being removably secured tosaid jig holding ring segment, saidjig holding. ring segmentibeing removably secured to said base members,and said base members being removably secured relative to said pair ofdragv ring segments so that when the core box is inverted said basemembers can be removed from said jig holding, ring segment and fromtheir coacting relation Withsaid drag segments, said jig holding ringsegment can then .be removed from saidpair of jigs, and said pair ofjigs can then be removed from the blades inserted therein.

'7. In a core boxfor use in forming turbine blade holding core segmentsembodying spaced curved blades extending transversely there- ,througlrand: presenting inner and outer free end portions adapted to have innerandputer ring segments cast integrally thereto, a bottom and dragoringconstruction comprising inner and outer base members disposed inspacedconcentric relation,.a jig holding ring segment disposed between.saidbase members, a pair of inner and outer jigs, disposed in spacedconcentric relation on; the ,topportion of said jig. holding ringsegment, said pair .of jigs being shaped to en-- gage longitudinally;spaced intermediate edge portions of blades inserted therein to therebyposition and firmly hold the bladesin a predetermined angular relation,a pair of inner and outer drag ring segments disposed in spacedconcentric relation and coacting with said base members to formtherewith spaced concentric surfaces shaped to position and retainthereagainst inner and outer series of filler blocks adapted to beassembled between the inner and outer end portions of blades held insaid pair of jigs, and said pair of drag rings being spaced apart adistance commensurate with the length of the blades to be positioned andheld in said pair of jigs so as to form with the exposed top portions ofsaid base members and with said jig holding ring segment and jigs achannel in which the blades and filler blocks can be quickly andaccurately assembled simply by alternately placing in abutting relationon said concentric positioning and retaining surfaces and in said pairof jigs a pair of inner and outer filler blocks and a blade,respectively.

8. In a core box for use in forming turbine blade holding core segmentsembodying spaced curved blades extending transversely therethrough andpresenting inner and outer free end portions adapted to have inner andouter ring segments cast integrally thereto, a bottom and drag ringconstruction comprising inner and outer base members disposed in spacedconcentric relation, a jig holding ring segment disposed between saidbase members, a pair of inner and outer jigs disposed in spacedconcentric relation on the top portion of said jig holding ring segment,said pair of jigs being shaped to engage longitudinally spacedintermediate edge portions of blades inserted therein to therebyposition and firmly hold the blades in a predetermined angular relation,a pair of inner and outer drag ring segments superimposed in spacedconcentric relation on portions of the tops of said base members andforming with the exposed portions of the tops of said base membersspaced concentric surfaces shaped to position and retain thereagainstinner and outer series of filler blocks adapted to be assembled betweenthe inner and outer end portions of blades held in said pair of jigs,and said pair of drag rings being spaced apart a distance commensuratewith the length of the blades to be positioned and held in said pair ofjigs so as to form withjthe exposed top portions of said base membersand with said jig holding ring segment and jigs a channel in which theblades and filler blocks can be quickly and accurately assembled simplyby alternately placing in abutting relation on said concentricpositioning and retaining surfaces and in said pair of jigs a pair ofinner and outer filler blocks and a blade, respectively.

9. In a core box for use in forming turbine blade holding core segmentsembodying spaced curved blades extending transversely therethrough andpresenting inner and outer free end portions adapted to have inner andouter ring segments cast integrally thereto, a bottom and intermediateedge a trie relation on and forming with the top por- 75 tion of saidbase ring segment spaced concentric surfaces shaped to position andretain thereagainst inner and outer series of filler block's adapted tobe assembled between the inner and outer end portions of blades held insaid pair of jigs, blades held in said pair of jigs and inner and outerseries of filler blocks disposed on said positioning and retainingsurfaces and between the inner and outer end portions of said blades,removable clamping means superimposed on said series of filler blocks inspaced concentric relation, and a jig ring segment removably secured inspaced concentric relation between said clampin means and the upperportions of said drag rings and in engagement with an intermediateportion of the adjacent edge of each of the blades held in said pair ofjigs.

10. In a core box for use in forming turbine blade holding core segmentsembodying spaced curved blades extending transversely there through andpresenting inner and outer free end portions adapted to have inner andouter ring segments cast integrally thereto, a bottom and drag ringconstruction comprising inner and outer base members disposed in spacedconcentric relation, a jig holding ring segment disposed between saidbase members, a pair of inner and outer jigs disposed in spacedconcentric relation on the top portion of said jig holding ring segment,said pair of jigs being shaped to engage longitudinally spacedintermediate edge portions of blades inserted therein to therebyposition and firmly hold the bladesin a predetermined angular relation,a pair of inner and outer drag ring segments disposed in spacedconcentric relation and coacting with said bottom members to formtherewith spaced concentric surfaces shaped to position and retainthereagainst inner and outer series of filler blocks adapted to beassembled between the inner and outer end portions of blades held insaid pair of jigs, blades held in said pair of jigsand inner and outerseries of filler locks disposed on said positioning and retainingsurfaces and between the inner and outer end portions of said blades,removable clamping means superimposed on said series of filler blocks inspaced concentric relation, and a jig ring segment removably secured inspaced concentric relationbetween said clamping means and the upperportions of said drag rings and in engagement with the adjacent edge ofeach blade at a point intermediate the longitudinally spaced oppositeedge portions thereof which are engaged by said pair of jigs. v i

11. In a core box for use informing turbine blade holding core segmentsembodying spaced curved blades extending transversely therethrough andpresenting inner and outer free, end portions adapted to have inner andouter ring segments cast integrally thereto, a bottom and drag ringconstruction comprising inner and outer base members disposed in spacedconcentric relation, a jig holding ring segment disposed between saidbase members, a pair of inner and outer jigs disposed in spacedconcentric relation on the top portion of said jig holding rin segment,said pair of jigs being shaped to engage longitudinally spacedintermediate edge portions of bladesinserted therein to thereby positionand firmly hold the blades in a predetermined angular relation, a pairof inner and outer drag ring segments superimposed in spaced concentricrelation on portions of thetops of said base members and forming withtheexposed portions of the tops of said base members spaced concentricsurfaces shaped to position and retain thereagainst inner and outerseries of filler blocks adapted to be assembled between the inner andouter end portions of blades held in said pair of jigs, said pair ofdrag rings being spaced apart a distance commensurate with the length ofthe blades to be positioned and held in said pair of jigs so as to formwith the exposed top portions of said base members and with said jigholding ring segment and jigs a channel in which the blades and fillerblocks can be quickly and accurately assembled simply by alternatelyplacing in abutting relation on said concentric positioning andretaining surfaces and in said pair of jigs a pair of inner and outerfiller blocks and a blade, respectively, blades held in said pair ofjigs and inner and outer series of filler blocks disposed on saidpositioning and retaining surfaces and between the inner and outer endportions of said blades, removable clamping means superimposed onsaidseries of filler blocks in spaced concentric relation, and a jig ringsegment removably secured in spaced concentric relation between saidclamping means and the upper portions of said drag rings and inengagement with an intermediate portion of the adjacent edge of each ofthe blades held in said pair of jigs.

12. In a core box for use in forming turbine blade holding core segmentsembodying spaced curved blades extending transversely therethrough andpresenting inner and outer free end portions adapted to have inner andouter ring segments cast integrally thereto, a bottom and drag ringconstruction comprising inner and outer base members disposed in spacedconcentric relation, a jig holding ring segment disposed between saidbase members, a pair of inner and outer jigs disposed in spacedconcentric relation on the top portion of said jig holding ring segmentand presenting pairs of downwardly inclined and transversely extendingalined notches terminating in undercut portions providing pairs oftransversely extending alined grooves adapted to receive snugly thereinlongitudinally spaced portions of the outlet edge of a curved blade,said pairs of notches being shaped to guide the outlet edge of a curvedblade downward into the grooved portions thereof and to-retain the bladeinserted therein in a predetermined angular relation, a pair of innerand outer drag ring segments disposed in-spaced concentric relation andcoacting with said base members to form therewith spaced concentricsurfaces shaped to position and retain thereagainst inner and outerseries of filler blocks adapted tobe assembled between the inner andouter end portions of blades inserted and held in said pairs of notches,

blades disposed in each pair of said notches and inner and outer seriesof filler blocks disposed on said positioning and retaining surfaces andbetween the'inner and outer end portions of said blades, removableclamping means superimposed on said series of filler blocks in spacedconcentric relation, and a jig ring segment removably secured in spacedconcentric relation between said clamping means and the upper portionsof said therethrough and presenting inner and outer free end portionsadapted to have inner and outer ring segments cast integrally thereto, abottom"v and drag ring construction comprising inner and outer basemembers secured in spaced concentric relation, a jig holding ringsegment disposed in and substantially closing the space between saidbase members, a pair of inner and outer blade holding jigs removablysecured in spaced concentric relation on the top portion of said jigholding ring segment and presenting pairs of downwardly inclined andtransversely extending notches terminating in undercut portionsproviding pairs of transversely extending alined grooves adapted toreceive snugly therein longitudinally spaced portions of the outlet edgeof a curved blade, said pairs of notches being shaped to guide the outeredge of a curved blade downward into the grooved portions thereof and toretain the blade inserted therein in a predetermined angular relation,said base members having portions of the tops thereof shaped toconcentrically position and support thereon a pair of inner and outerdrag ring segments, 9. pair of inner and outer drag ring segmentssuperimposed on said portions of the tops of said base members andforming with the exposed portions thereof concentric surfaces shaped toposition and retain thereagainst inner and outer series of filler blocksadapted to be disposed between the free inner and outer end portions ofblades disposed in said pairs of notches, blades disposed in each pairof said notches and inner and outer series of filler blocks disposed onsaid positioning and supporting surfaces and between the inner and outerend portions of said blades, removable clamping means superimposed onsaid filler blocks, and a removable jig ring segment disposed in spacedconcentric relation between said clamping means and the upper portion ofsaid drag rings andengaging the inlet edge of each blade at a pointintermediate the longitudinally spaced outlet edge portions thereofwhich are disposed in a pair of said notches.

14. In a core box for use in forming turbine blade holding core segmentsembodying angularly spaced curved blades extending, transverselytherethrough and presenting inner and outer free end portions adapted tohave inner and outer ring segments cast integrally thereto, a bottomconstruction comprising inner and outer base members positioned inspaced concentric relation, a jig holding ring segment disposed betweenand substantially closing the space between said base members, a pair ofinner and outer blade holding jigs secured in spaced concentric relationon the top portion of said jig holding ring segment and presenting pairsof downwardly inclined and transversely extending notches terminating inundercut portions providing transversely extending alined groovesadapted to receive snugly therein longitudinally spaced portions of theoutlet edge of a curved blade, said pairs of notches being shaped toguide the outlet edge of a curved blade downward into the groovedportions thereof and to retain the blade inserted therein in apredetermined angular relation, said jigs being removably secured tosaid jig holding ring segment, and said jig holding ring segment beingremovably supported between said bottom members so that when the corebox has been partially rammed and inverted, said bottom members can beremoved from said jig holding ring segment, said jig holding ringsegment can then be removed from said pair of jigs, and said pair ofjigs can then be removed from the outlet edges of the blades inserted insaid pairs of notches.

15, In a core box for use in forming turbine blade holding 'coresegments embodyingangularly spaced curved blades extending transverselytherethrough and presenting inner and outer free end portions adapted tohave inner and outer ring segments cast integrally thereto, a bottomconstruction comprising inner and outer base members disposed in spacedconcentric relation, a jig holding ring segment disposed between saidbase members, a pair of inner and outer blade holding jigs disposed inspaced concentric relation on the top portion of said jig holding ringsegment and presenting pairs of downwardly inclined and transverselyextending alined notches terminating in undercut portions providingtransversely extending grooves adapted to receive snugly thereinlongitudinally spaced portions of the ou let edge of a curved blade,said pairs of notches being shaped to guide the outlet edge of a curvedblade downward into the grooved portions thereof and to retain the bladeinserted therein in a predetermined angular relation, said jig holdingring being removable from said pair of jigs when the core box isinverted, and said pair of jigs being then removable from the outletedges of the blades inserted in said pairs of notches.

16. In a core box for use in forming turbine blade holding core segmentsembodying angularly spaced curved blades extending transverselytherethrough and presenting inner and outer free end portions adapted tohave inner and outer ring segments cast integrally thereto, a bottomconstruction comprising a base ring segment and a pair of inner andouter blade holding jigs disposed in spaced concentric relation on thetop portion of said base ring segment and presenting upwardly facingpairs of downwardly inclined and transversely extending alined notchesterminating in undercut portions providing transversely extendinggrooves adapted to receive snugly therein longitudinally spaced portionsof the outlet edge of a curved blade, said pairs of notches being shapedto guide the outlet edge of a curved blade downward into the groovedportions thereof and to retain the blade inserted therein in apredetermined angular relation.

17. In a method of forming turbine blade holding core segments embodyingspaced curved blades extending transversely therethrough and presentinginner and outer free end portions adapted to have inner and outer ringsegments cast integrally thereto, the steps comprising forming a corebox having a bottom portion including inner and outer filler blockpositioning and retaining surfaces disposed in spaced concentricrelation with respect to each other and with respect to the sides ofsaid box and including a pair of blade positioning and holding jigsdisposed between and in spaced concentric relation with respect to saidinner and outer surfaces and in spaced concentric relation with respectto each other, alternately placing a pair of inner and outer fillerblocks on said inner and outer surfaces and a blade in said pair of jigswith the inner and end portion of each blade abutting the proximateportions of said pair of filler blocks to thereby form a series ofangularly spaced blades having the inner and outer end portions of eachblade disposed between and enclosed by adjacent pairs of said fillerblocks, clamping said filler blocks and blades in said box, ramming saidbox with a coreforming material to a depth sufficient to cover saidblades, removing said clamping means and placing a metallic ring segmentarbor on said core forming material and in spaced concentric relationwith respect to the sides of said box, completing the ramming of said,box with core forming material, inverting said box and removing saidbottom: portion, placing cope ring segments in spaced concentricrelation on the top portions'of the sides of the inverted box andramming suificient core forming material between said cope segments tocover the adjacent edges of the blades, placing a metallic ring segmentarbor on said core forming material and in spaced concentric relationwith respect to the sides of'said cope segments, completing the rammingof the space between said copev segments with the core forming material,removing the remaining portions of the box from the core formed therein,and removably securing a tie rod between the free exposed end portionsof each arbor.

18. In a method of forming turbine blade holding core segments embodyingspaced curved blades extending transversely therethrough and presentinginnerv and outer free end portions adapted to have inner and outer ringsegments cast integrally thereto, the steps comprising forming, acorebox having a bottom portion including inner and outer filler blockpositioning and retaining surfaces disposed in spaced concentricrelation with respect to each other and with respect to the sides ofsaid box and including a pair of blade positioning and holding jigsdisposed between and in spaced concentric relation with respect to saidinner and outer surfaces and in spaced concentric relation with respectto each other, alternately placing a pair of inner and outer fillerblocks on said inner and outer surfaces and a blade in said pair of jigswith the inner and outer end portion of each blade abutting theproximate portions of said pair of filler blocks to thereby form aseries of angularly spaced blades having the inner and outer endportions'of each blade disposed between and enclosed by adjacent pairsof said filler blocks, clamping said filler blocks and blades in saidbox, ramming said box with a core forming material to a dep h sufficientto cover said blades, removing said clamping means and placing ametallic ring segment arbor on said Y completing the ramming of said boxwith core forming material, inverting said box and removing said bottomportion, placing cope ring segments in spaced concentric relation on thetop portions of the sides of the inverted box and ramming sufiicientcore forming material between said cope segments to cover he adjacentedges of the blades, placing a metallic ring segment arbor on said coreforming material and in spaced concentric relation with respect to thesides of said cope segments, and completing the ramming of the spacebetween said cope segments with the core forming material.

.19. In a method of forming turbine blade holding core segmentsembodying spaced curved blades extending transversely therethrough andpresenting inner and outer free end portions adapted to have inner andouter ring segments cast integrally thereto, the steps comprisingforming a core box having bottom portion including inner and outerfiller block positioning and retaining surfaces disposed in spacedconcentric relation with respect to each other and with respect to thesides of said box and including a pair of blade positioning and holdingjigs disposed between and in spaced concentric relation with respect tosaid inner and outer surfaces'and in spaced concentric relation withrespect to each other, alternately placing a pair 20. In a core for usein forming turbine blade 1 holding core segments embodying a series ofspaced blades extending transversely therethrough and presenting inneand outer free end portions adapted to have inner and outer ringsegments cast integrally thereto, a core reinforcing constructioncomprising a pair of metallic ring segment arbors extending throughoutthe length of the core on either side of and in close proximity withrespect to the inlet and on let edges of the spaced blades extendingtransversely therethrough and terminating in exposed Iree end portions,and a tie rod connecting the free end portions of each arbor.

21. In a core box for use in forming blade holding core segmentsembodying spaced blades extending transversely therethrough andpresenting inner and outer free end portions adapted to have inner andouter ring segments cast integrally thereto, a bottom cons ructioncomprising a base ring segment presenting inner and outer concentricdrag segment positionin and supporting surfaces and inner and outerconcentric fiiler block positioning and supporting surfacesdisposedbetween and in proximity to said inner and outer ring segmentsurfaces respectively, and. a pair of blade positioning and holding jigsegments disposed on said base ring segment in spaced concentricrelation between said filler block positioning and supporting surfaces.

22. In a core box for use in forming blade holding core segmentsembodying spaced blades extending transversely therethrough andpresenting inner and outer free end portions adapted to have inner andouter ring segments cast integrally thereto, a bottom constructioncomprising a base ring segment presenting inner and outer concentricdrag ring segment positioning and supporting surfaces and inner andouter concentric filler block positioning and supporting surfacesdisposed between and in proximity to said inner and outer drag ringsegment surfaces respectively, and a pair of biade positioning andholding jig segments disposed on said base ring segment between saidfiller block positioning and supporting surfaces in spaced concentricrelation with respect to each other and with respect to said fillerblock positioning and supporting surfaces.

23. In a core box for main forming blade holding core segments embodyingspaced blades extending transverseiy therethrough and presenting innerand outer free end portions adapted to have inner and outer ringsegments cast integrally thereto, a botto a construction comprising abase ring segment presenting inner and outer concentric drag ringsegment supporting surfaces cmbodying drag ring segment positioningmeans thereon and presenting between and in proximity to said inner andouter drag ring segment surand outer concentric drag ring segmentpositioning and supporting surfaces and inner and outer concentricfiller block positioning and supporting surfaces disposed between and inproximity to said inner and outer drag ring segment surfacesrespectively, and a pair of blade positioning and holding jig segmentsdisposed on said base ring segment in spaced concentric reiation betweensaid filler block positioning and supporting surfaces and presen 'ngpairs of alined upwardly opening notches arranged to engagelongitudinaliy spaced edge portions of blades inserted thereinintermediate the free end portions thereof.

25. In a core box for use in forming blade holding core segmentsembodying spaced blades X-' tending transversely therethrough andpresenting inner and outer free end portions adapted to have inner andouter ring segments cast integrally thereto, a base ring segmentpresenting inner and outer concentric drag ring segment positioning andsupporting surfaces and inner and outer concentric filler blockpositioning and supporting 7 surfaces disposed between and in proximityto said inner and outer drag ring segment surfaces respectively, a pairof blade positioning and holding jig segments disposed on said base ringsegment in spaced concentric relation between said filler blockpositioning and supporting surfaces and presenting pairs of alinedupwardly opening notches arranged to engage longitudinally spaced edgeportions of blades inserted therein intermediate the free end portionsthereof, a pair of inner and outer drag ring segments mounted on saidinner and outer drag ring supporting surfaces, respectively, and bladesmounted in said jig segments with their ends abutting the opposed innerside surfaces of said drag ring segments.

26. In a core box for use in forming blade holding core segmentsembodying spaced blades eX- tending transversely therethrough andpresenting inner and outer free end portions adapted to have inner andouter ring segments cast integrally thereto, a base segment embodying apair of concentric blade positioning and holding jig segments presentingpairs of alined upwardly opening notches arranged to engagelongitudinally spaced edge portions of blades inserted thereinintermediate the free end portions thereof, a pair of inner and outerdrag ring segments coacting with said base segment to form a channeladapted to have blades positioned transversely therein by inserting anintermediate edge portion of each blade in a pair of said notches,bladespositioned in said pairs of notches, and a superposed jig carryingring segment engaging the opposite edge portion of each blade at a pointintermediate the longitudinally spaced edge portions thereof which aredisposed in a pair of said notches.

ALBERT F. PFEIFFER.

